1. Field of Invention
The invention concerns a disposable connector intended to be used for medical purposes; in particular a connector intended to be used during hemofiltration and/or hemodiafiltration treatments.
2. Description of the Prior Art
Hemodialysis treatments require an extracorporeal blood circulation. The blood circuit comprises an out-tube intended to supply blood from the patient to the hemodialysis machine, where blood is passed through a filter in order to remove waste products. The blood circuit further comprises an in-tube intended to supply filtered blood from the hemodialysis machine back to the patient.
Most of the recent hemodialysis machines are designed to perform also the so called hemofiltration and/or hemodiafiltration treatments. Hemofiltration treatment implies the removal of some waste water from the blood and, accordingly, it needs also to compensate the removal by means of the addition of saline solution, i.e. the so called substitution liquid. Where such treatment is combined with a traditional hemodialysis, the so called hemodiafiltration treatment is obtained. In the following, for sake of simplicity, with the term “hemofiltration” reference will be made both to the actual hemofiltration and to the hemodiafiltration treatments.
Such recent hemodialysis machines further need a substitution line intended to supply the substitution liquid in the blood flow directed to the patient. According to some machines, for example the one disclosed in EP 2 059 279, the substitution line is obtained from the water system (see FIG. 1). In particular, water corning from the water system is subjected to an ultrafiltration treatment by the machine itself, then in the ultrafiltered water salts are dissolved which are needed for making it a physiological solution usable as a substitution liquid. Thus the machine comprises a port (shown in detail in FIGS. 2 and 3) intended to supply the substitution liquid.
The substitution line of the disposable tubing set needs to be connected to the substitution port of the machine by means of a disposable connector. A disposable connector according to the prior art is shown in FIGS. 4 and 5. Such prior art connector, although widely used and appreciated, is not defect-free. It comprises four different components: a main body, a fixing thread, an o-ring seal, and a slotted membrane. In addition, the prior art connector comprises at least one removable cap or, in the most complicated version shown in FIG. 4, two removable caps. The main body and the fixing thread are usually obtained from polycarbonate or some other rigid material suitable for medical use. The o-ring seal and the slotted membrane are usually obtained from silicone or some other soft material suitable for medical use.
The assembly of the disposable connector of the known type requires that the membrane is inserted in its seat obtained along the duct of the main body, till it rests on the shoulder. Then also the fixing thread has to be inserted along the same duct, till it contacts the membrane. The main body and the fixing thread are then joined together by means of ultrasound welding, so as to hold the silicone membrane in place. The assembly of the known connector is then finished by slipping the o-ring seal along the main body to its seat and, in case, by putting on the two caps.
As can be easily appreciated by the skilled person, the prior art connector is quite complex and relatively expensive. The relatively high number of pieces, with respect to the overall dimensions of the connector, requires a time-consuming assembly. Moreover, the ultrasound welding step requires both dedicated equipments and qualified personnel.